Compression relief mechanism for starting internal combustion engines



United States Patent [72] Inventor Wilford B. Burkett 3,342,170 9/1967 McCreary [21] A I N sggigcsgalisades, California 3,418,992 12/1968 Anderson 123/182 pp o. [22] Filed March 1, 1968 FOREIGN ENTS Communion ufser. No 371,519 4/1932 Great Britain 123/18'2 512,860 Dec. 10,1965 abandbned 1,187,191 3/1959 France 123/182 [45] Patented Nov. 10-, 1970 Primary ExaminerMark M. Newman [73] A i M c ll h C ti AnorneyBurns, Doane. Benedict, Swecker & Mathis Los Angeles, California a corporation of Wisconsin [54] COMPRESSION RELIEF MECHANISM FOR An nternal COI'I'IbUSIIO II engine having a cylinder 6 Claims, 4 Drawing Figs. and p ston operat ve there n, the cylinder wall havlngan openmg WIIh a cylindrical portlon connected to the exterior of the U.S. cylinder wall a valve eat at its inner end and a port extending f Cl Foll 1378 therefrom to the cylinder, a reciprocable valve in the opening [50] held of Search 123/182 having a seanng surface f engaging the Seat undelthe action of a spring, said valve having a protrusion which extends into [56] References cued and fills the port when the valve is seated, the valve being UNITED STATES PATENTS manually operable to an unseated position with the protrusion 1,890,584 12/1932 Mardin 123/182 withdrawn from the port to decompress the cylinder.

"33 7 53 43 35 70 v Z; 2 49. a2 g I 72 3 44 "3a v 43- I A 30 Patented Nov. 10, 1970 v 3,538,899

Sheet 1 of2 INVENTOR.

WHANN 6 Mc MAN/64L l/l o na s for A ly/Iran) Mm a awe/ RELATED APPLICATION This application is a continuation of my prior application Ser. No. 512,860 filed Dec. 10, 1965 now abandoned.

GENERAL BACKGROUND, OBJECTS AND SUMMARY OF THE INVENTION This invention relates to a means to permit easy starting of internal combustion engines, and more particularly, to a valve which, when open, relieves pressure from an engine cylinder to permit easy starting and idling. I

By way of example, two cycle engines receive and compress the fuel mixture in the cylinder with each revolution of the crankshaft and this tends to make the engines difficult to start. It has been found that by relieving the compression in the cylinder on starting by a valved opening through the cylinder that starting is enhanced. It has also been found that such openings tend to clog during operation of the engine so that their effectiveness is destroyed.

It is therefore an object of the present invention to provide an improved compression relief mechanism for internal combustion engines.

It is another object of the invention to provide a compression relief valve which prevents clogging of the valve port and which cleans the port as the valve is closed.

It is still another object of the invention to provide a valve, as described in the preceding paragraphs, which, when open, relieves compression during starting and permits idling after starting.

It is a further object of the invention to provide a valve, as described in the preceding paragraphs, having a valve port which is closed by the piston on the compression stroke so as to permit an adequate compressed mixture in the compression chamber even though the valve is open.

Further objects and advantages of the invention may be brought out in the following part of the specification wherein small details have been described for the competence of disclosure without intending to limit the scope of the invention which is set forth in the appended claims.

DRAWINGS Referring to the accompanying drawings, which are for illustrative purposes:

FIG. 1 is a partially cross-sectioned view of a two cycle gasoline engine including the present invention;

FIG. 2 is a fragmentary view of the engine shown in FIG. 1 and illustrating the invention in position for starting of the engine;

FIG. 3 is a fragmentary view, taken as indicated by the line 3-3 of FIG. 2; and

FIG. 4 is an isometric view of the compression relief valve, according to the invention.

GENERAL DESCRIPTION Referring again to the drawings, there is shown in FIG. 1 a two cycle gasoline engine generally designated as 10. The engine has a crankcase 11 and extending therethrough is a crankshaft 12. A connecting rod 13 has its lower end 17 pivotally and bearing mounted on the crankshaft and has its upper end, not shown, similarly connected to the engine piston 17. An inlet 18 is provided to the interior of the crankcase and a passage 19 extends in the engine wall to connect the crankcase to a cylinder 20 above the piston to provide an inlet for the gas and air mixture to the cylinder when the piston is at or near the bottom of its stroke.

Immediately above the piston is an exhaust port 24, connected through a passage to a muffler 26. Surrounding the cylinder and piston is an engine frame 29 and extending into the frame and through the cylinder wall, formed in part by a cylinder liner 30, is a compression relief port 31, as best seen in FIG. 2.

At the upper end of the cylinder 20, there is a cylinder head portion 27 having a hemispherical recess 28 forming a firing chamber. Extending into the chamber 28 are the spark plug contacts 33 and 34. 1

Outwardly of the relief port 31 is a valve seat 32 opening into a valve chamber 35. Slidably engaged in the chamber 35 is a cylindrical valve member 36, as may'be seen in FIG. 4. Inwardly extending on the valve member is a conical valve 37' which closes on the valve seat 32.

As may be seen in FIG. 1, when the valve is in the closed position a cylindrical protrusion 38, extending inwardly of the valve on the valve member, is snugly and slidably engaged in the cylindrical port 31. The inner end 41 of the protrusion 38 is flat and when the valve is closed, the end 41 is substantially flush with the inner surface of the cylinder 20, but is positioned so that the piston 17 can move upwardly past it in the cylinder without making contact. That is, the flat end 41 is positioned to be substantially tangential with the surface of the cylinder. The inner end of the protrusion may also be made to be cylindrical so as to conform to and be flush with the cylinder wall and thereby, provide clearance for the movement of the piston.

When the valve 37 is open and the piston is down, as best seen in FIG. 2, the cylinder 20 is in communication with the exhaust 24 by means of the valve port 31, the valve chamber 35, and a passage 42.

Adjacent the outer end of the valve member 36 is a vertically extending, channel-shaped slot 43 having end walls 44 and 45. Slidably engaged with the end walls 44 and 45 are curved surfaces 47 and 48 on the lower end 49 of a lever 50, pivotally mounted at 53, the pivot being supported on the engine frame. The lever 50 has an upper end pivotally connected at 54 to an actuating rod 55. The rod extends through and is supported for slidable engagement in an opening 56 in a bracket 57 on the engine frame. A washer 59 is secured to the rod and one end of a coil spring 60, surrounding the rod, abuts the washer 59. The other end of the spring abuts a washer 61, slidably engaged on the rod. The washer 61 is held in abutment with a bracket member 62 by the spring. The rod 55 extends through a slot-shaped opening 65 in the bracket 62 and the outer end ofthe rod is secured to a sleeve 66 having a discshaped handle 67 at its end.

As may be best seen in FIGS. 1-3, a portion 68 of the engine frame has a key-shaped opening 70, having an upper portion 71 which is generally circular and a lower portion 72 of slot shape. When the valve is in its closed position as shown in FIG. 1, the sleeve 66 is slidably engaged in the upper portion 71 and the valve is held closed by means of the spring acting on the washer 59 so as to cause the lower end 49 of the lever to be held toward the right. To open the valve, the handle 67 is moved toward the right, as shown in FIG. 2, causing the lever end 49 to move to the left in its engagement on the wall 44 so as to move the valve off of its seat and the protrusion 38 out of the opening 31. To maintain the valve in its open position, the handle is moved downwardly on the frame member 68, the rod 55 moving downwardly in the slots 65 and 72, and the sleeve being positioned in abutment with the frame member 68, as indicated in FIGS. 2 and 3.

In the drawings, the piston 17 is shown in its lowest position after it has completed its power stroke. As it moves upwardly in its compression stroke there is a partial vacuum formed in the crankcase so as to cause a flow of combustible mixture into the crankcase 11 through the inlet 18. In starting the engine, if the piston has moved upwardly for the first time, there will not have been a proper mixture in the chamber 20 and the engine will not have started. The piston then will move downwardly again, causing compression in the crankcase and causing the mixture to flow from the crankcase through the passage 19 into the chamber 20.

' As the piston rises again in its compression stroke, the mixture in the cylinder 20 creates a resistance to the turning over and starting of the engine. To relieve this compression the valve 37 is opened and the handle 67 is put into the position shown in FIG. 2 to lock the valve open. This permits, as the piston is rising, some of the mixture to be exhausted through the port 31, the valve chamber 35, the passage 42 into the exhaust 24, 25 and finally into the muffler 26, the exhaust passage 24 having been closed to the chamber by the piston 17. As the piston continues to rise, it closes the valve port 31 to the chamber 20 and permits a sufficient amount of mixture to remain in the cylinder 20 and in the firing chamber 77 so that when the spark plug fires, combustion will occur and the engine will start.

Because of the positioning of the valve 37 and its port 31, whereby the port is closed by the piston 17 on the compression stroke, there is always sufficient mixture remaining in the cylinder and in the firing chamber to sustain good idling. Thus, it is not necessary that the valve 37 be closed as soon as the engine starts.

During operation of the engine, there is a tendency for carbon to clog the valve port 31, but when the valve is closed for normal running of the engine, the protrusion 38 slides into the port 31 and cleans any carbon or other debris out of it. Further, during normal operation the protrusion plugs up the port 31 and prevents any carbon from depositing in it. This prevents the valve opening from becoming inoperative as has occurred in the prior art. The dimensions in the operable engine shown are as follows: diameter of cylinder 20, 2.218", piston stroke 1.63", diameter of valve port 31, 0.160", distance of port 31 from the cylinder head 76, 0.31", and the radius of hemispherical firing chamber 77, 0.656". The diameter of the passage 42 is approximately equal to that of the port 31.

The invention and its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts of the invention without departing from the spirit and scope thereof or sacrificing its material advantages, the arrangement hereinbefore described being merely by way of example.

l claim:

1. An internal combustion engine comprising:

cylinder means;

cylinder head means closing one end of said cylinder means;

piston means mounted for reciprocation within said cylinder means;

exhaust passage means operable to discharge combustion products from the interior of said cylinder means;

inlet passage means operable to supply combustible lluid to the interior ofsaid cylinder means;

ignition means operable to ignite combustible fluid supplied to the interior of said cylinder means;

compression relief passage means communicating with the interior passage means of said cylinder means and interposed along the axis of reciprocation of said piston means, between the axial location of said exhaust port means and said cylinder head means, said relief passage meansincluding:

port means in said cylinder means communicating with, and extending laterally outwardly of the interior of said cylinder means;

a valve seat;

a relief valve supporting passage; and

a'v enting passage communicating with said relief valve supporting passage;

a compression relief valve including:

a valve body reciprocably mounted in said relief valve supporting passage;

a valve head abuttingly engageable with said valve seat, said valve head, when spaced from said valve seat, being spaced at least in part from said relief valve supporting passage to define a passage portion providing iluid connnunieation between said venting passage and said port means; and

a port cleaning plug snugly and slidably engageable with said port means, said cleaning plug being operable, in response to reciprocation within said port means, to

clean carbon deposits therefrom and, when disposed within said port means, being operable to plug said port means and prevent carbon from depositing therein; said port cleaning plug having a periphery operable to cooperate with said port means and prevent accumulation of carbon is said port means and isolate said valve seat and valve head from communication with the interior of said cylinder means; operating means for moving said compression relief valve through said valve supporting passage and said port means; said piston means being operable, in moving through said cylinder means toward said cylinder head means, to close said exhaust passage means and then said port means; and means operable to position said plug means so as to plug said port means while combustion products are discharging through said exhaust passage means under the in fluence of movement of said piston means, and thereby prevent carbon from depositing in said port means. 2. An internal combustion engine comprising: cylinder means; cylinder head means closing one end of said cylinder means; piston means mounted for reciprocation within said cylinder means; exhaust passage means operable to discharge combustion products from the interior of said cylinder means; inlet passage means operable to supply combustible fluid to the interior of said cylinder means; ignition means operable to ignite combustible fluid supplied to the interior of said cylinder means; compression relief passage means communicating with the interior passage means of said cylinder means and interposed along the axis of reciprocation of said piston means, between the axial location of said exhaust port means and'said cylinder head means, said relief passage means including:

wall means of said cylinder meansdefining port means formed directly in said cylinder means and communicating with, and extending laterally outwardly of the interior of said cylinder means;

a valve seat;

a reliefvalve supporting passage; and

a venting passage extending between and communicating with said exhaust passage means and said relief valve supporting passage;

a compression relief valve including:

a valve body reciprocably mounted in said relief valve supporting passage;

a valve head abuttingly engageable with said valve seat, said valve head, when spaced from said valve seat, being spaced at least in part from said relief valve supporting passage to define a passage portion providing fluid communication between said venting passage and said port means; and

a port cleaning plug snugly and slidably engageable with said wall means of said cylinder means defining said port means, said cleaning plug being operable, in response to reciprocation within said port means, to clean carbon deposits therefrom and when disposed within said port means, being operable to plug said port means and prevent carbon from depositing therein;

said port cleaning plug having a periphery operable to cooperate with said port means and prevent accumulation of carbon in said port means and isolate said valve seat and valve head from communication with the interior of said cylinder means;

manually operable operating means for selectively moving said compression relief valve through said valve aupporting passage and said port means;

said piston means being operable in moving through said cylinder means toward said cylinder head means to close said exhaust passage means and then said port means; and

holding means operable to position said plug means so as to plug said port means while combustion products are discharging through said exhaust passage means under the influence of movement of said pistonmeans and thereby prevent carbon from depositing in said port means. 3. An internal combustion engine comprising: cylinder means; cylinder head means closing one end of said cylinder means; piston means mounted for reciprocation within said cylinder means; exhaust passage means operable to discharge combustion 1 products from the interior of said cylinder means; inlet passage means operable to supply combustible fluid to the interior of said cylinder means; ignition means operable to ignite combustible fluid supplied to the interior of said cylinder means; compression relief passage means communicating with the interior passage means of said cylinder means and interposed along the axis of reciprocation of said piston means, between the axial location of said exhaust port means and said cylinder head means, said relief passage means including: i wall means of said cylinder means defining port means formed directly in said cylinder means and communicating with, and extending laterally outwardly of the interior of said cylinder means; a frustoconical valve seat; a relief valve supporting passage; a slot intersecting and communicating with said relief valve supporting passage; and a venting passage extending between and communicating with said exhaust passage means and said relief valve supporting passage;

a compression relief valve defined by a unitary solid body including:

a solid valve body reciprocably mounted in said relief valve supporting passage;

a frustoconical valve head abuttingly engageable with i said valve seat, said valve head, when spaced from'said valve seat, being spaced at least in part from said relief valve supporting passage to define a passage portion providing fluid communication between said venting passage and said port means;

a solid port cleaning plug snugly and slidably engageable with said wall means of said cylinder means defining said port means, said cleaning plug being operable, in response to reciprocation within said port means, to clean carbon deposits therefrom and when disposed within said portmeans, being operable to plug and substantially completely fill said port means and prevent carbon from depositing therein; and

a slot formed on the periphery of said valve body and extending transversely of the axis thereof;

said port cleaning plug having a periphery operable to cooperate with said port means and prevent accumulation of carbon in said port means and isolate said valve seat and valve head from communication with the interior of said cylinder means;

manually operable operating means for selectively moving said compression relief valve through said valve supporting passage and said port means, said operating means including:

a lever pivotally mounted on said cylinder means and having one end projecting through said passage means slot and into said valve body slot and another operating end; and

a manually manipulatable rod slidably mounted on said cylinder means and pivotally connected with said other end of said lever;

said piston means being operable in moving through said cylinder means toward said cylinder head means to close said exhaust passage means and then said port means; and

resilient holding means operable to position said plug means so as to plug said port means while combustion products are discharging through said exhaust passage means under the influence of movement of said piston means and thereby prevent carbon from depositing in said port means.

4. An internal combustion engine comprising:

cylinder means;

cylinder head means closing one end of said cylinder means;

piston means mounted for reciprocation within said cylinder means;

exhaust passage means operable to discharge combustion products from the interior of said cylinder means;

inlet passage means operable to supply combustible fluid to the interior of said cylinder means;

ignition means operable to ignite combustible fluid supplied to the interior of said cylinder means;

compression relief passage means communicating with the interior passage means of said cylinder means and interposed along the axis of reciprocation of said piston means, between the axial location of said exhaust port means and said cylinder head means, said relief passage means including:

port means in said cylinder means communicating with, and extending laterally outwardly ofthe interior of said cylinder means;

a valve seat;

a relief valve supporting passage; and

a venting passage communicating with said relief valve supporting passage;

a compression relief valve including:

a valve body reciprocably mounted in said relief valve supportingpa ssage;

a valve head abuttingly engageable with said valve seat, said valve head, when spaced from said valve seat, being spaced at least in part from said relief valve supporting passage to define a passage portion providing fluid communication between said venting passage and said port means; and

a port cleaning plug snugly and slidably engageable with said port means, said cleaning plug being operable, in response to reciprocation within said port means, to clean carbon deposits therefrom and, when disposed within said port means, being operable to plug said port means and prevent carbon from depositing therein;

operating means for moving said compression relief valve through said valve supporting passage and said port means;

said piston means being operable, in moving through said cylinder means toward said cylinder head means, to close said exhaust passage means and then said port means;

means operable to position said plug means so as to plug said port means while combustion products are discharging through said exhaust passage means under the influence of movement of said piston means, and thereby prevent carbon from depositing in said port means; and

said port cleaning plug having a terminus substantially flush with a cylindrical inner wall' of said cylinder means, said terminus being cylindrically curved so as'to substantially conform to the curvature of said cylindrical wall.

5. An internal combustion engine comprising:

cylinder means;

cylinder head means closing one end of said cylinder means;

piston means mounted for reciprocation within said cylinder means;

exhaust passage means operable to discharge combustion products from the interior of said cylinder means;

inlet passage means operable to supply combustiblefluid to t the interior of said cylinder means;

ignition means operable to ignite combustible fluid supplied to the interior of said cylinder means;

compression relief passage means communicating with the interior passage means of said cylinder means and interposed along the axis of reciprocation of said piston means, between the axial location of said exhaust port means and said cylinder head means, said relief passage means including:

wall means of said cylinder means defining port means formed directly in said cylinder means and communicating with, and extending laterally outwardly of the interior of said cylinder means;

a valve seat;

a relief valve supporting passage; and

a venting passage extending between and communicating with said exhaust passage means and said relief valve supporting passage;

a compression valve including:

a valve body reciprocably mounted in said relief valve supporting passage;

a valve head abuttingly engageable with said valve seat, said valve head, when spaced from said valve seat, being spaced at least in part from said relief valve supporting passage to define a passage portion providing fluid communication between said venting passage and said port means; and

a port cleaning plug snugly and slidably engageable with said wall means of said cylinder means defining said port means, said cleaning plug being operable, in response to reciprocation within said port means, to clean carbon deposits therefrom and when disposed within said port means, being operable to plug said port means and prevent carbon from depositing therein;

manually operable operating means for selectively moving said compression relief valve through said valve supporting passage and said port means; 7

said piston means being operable in moving through said cylinder means toward said cylinder head means to close said exhaust passage means'and then said port means;

holding means operable to position said plug means so as to plug said port means while combustion products are discharging through said exhaust passage means under the influence of movement of ,said piston means and thereby prevent carbon from depositing in said port means; and

said port cleaning plug having a terminus substantially flush with a cylindrical inner surface of said wall means of said cylinder means, said terminus being cylindrically curved so as to substantially conform to the curvature of said cylindrical inner surface.

6. An internal combustion engine comprising:

cylinder means;

cylinder head means closing one end of said cylinder means;

piston means mounted for reciprocation within said cylinder means;

exhaust passage means operable to discharge combustion products from the interior of said cylinder means;

inlet passage means operable to supply combustible fluid to the interior ofsaid cylinder means;

ignition means operable to ignite combustible fluid supplied to the interior of said cylinder means;

compression relief passage means communicating with the interior passage means of said cylinder means and interposed along the axis of reciprocation of said piston means, between the axial location of said exhaust port means and said cylinder head means, said relief passage means including:

wall means of said cylinder means defining port means formed directly in said cylinder means and communicating with, and extending laterally outwardly of the interior of said cylinder means;

a frustoconical valve seat;

a relief valve supporting passage;

a slot intersecting and communicating with said relief valve supporting passage; and

a venting passage extending between and communicating with said exhaust passage means and said relief valve supporting passage;

a compression relief valve defined by a unitary solid body including:

a solid valve body reciprocably mounted in said relief valve supporting passage;

a frustoconical valve head abuttingly engageable with said valve seat, said valve head, when spaced from said valve seat, being spaced at least in part from said relief valve supporting passage to define a passage portion providing fluid communication between said venting passage and said port means;

a solid port cleaning plug snugly and slidably engageable with said wall means of said cylinder means defining said port means, said cleaning plug being operable, in response to reciprocation within said ports means, to clean'carbon deposits therefrom and when disposed within said port means, being operable to plug and substantially completely fill said port means and prevent carbon from depositing therein; and

a slot formed on the periphery of said valve body and extending transversely of the axis thereof;

manually operable operating means for selectively moving said compression relief valve through said valve supporting passage and said port means, said operating means including:

a lever pivotally mounted on said cylinder means and having one end projecting through said passage means slot and into said valve body slot and another operating end; and

a manually manipulatable rod slidably mounted on said cylinder means and pivotally connected with said other end of said lever;

said piston means being operable in moving through said cylinder means toward said cylinder head means to close -said exhaust passage means and then said port means;

resilient holding means operable to position said plug means so as to plug said port means while combustion products are discharging through said exhaust passage means under the influence of movement of said piston means and thereby prevent carbon from depositing in said port means; and

said port cleaning plug having a terminus substantially flush with a cylindrical inner surface of said wall means of said cylinder means, said terminus being cylindrically curved so as to substantially conform to the curvature of said cylindrical inner surface. 

